It's been caused by a movement of lava at shallow depths towards the central crater of the Nyamulagira volcano, according to the latest data.

Nyamulagira's last major eruption was in 2011 - its biggest eruption in 100 years.

It is located right in the middle of Virunga national park, which is also home to endangered mountain gorillas.

If a fresh eruption happens, the lava would flow towards the park, the Goma Volcano Observatory warned on Monday evening.

There are currently no threats to the city of Goma, where around 670,000 people live according to UN estimates.

But volcanic ash and strands of cooled lava could be blown by wind into inhabited areas, the observatory added in a statement.

"We recommend that the people of Goma keep calm and go about their business freely," it said.

Residents have been urged to wash vegetables and use stored water, while airlines have also been told to consider the wind direction when flying over the Virunga region.

In May 2021, tens of thousands of people were evacuated from the city of Goma after Mount Nyiragongo erupted.